Counterweight removal device



March 26, 1968 1.. D. GRIDER 3,375,021

COUNTERWEIGHT REMOVAL DEVI CE Filed May 20, 1966 5 Sheets-Sheet 1 INVENTOR LYLE D. GRIDER fW/MM ATTORNEY March 26, 1968 L. D. GRIDER 3,375,021

COUNTERWEIGHT REMOVAL DEV I CE Filed May 20, 1966 3 Sheets-Shet z INVENTOR LYLE D. GRIDER ATTORNEY March-26;, 1968.1 L. D. GR IDER C OUNTER WEIGHT REMOVAL DEVICE 3 Sheets-Sheet 3 Filed May 20, 1966 INVENTOR LYLE D.GR|DER ATTORNEY.

United States Patent 3,375,021 COUNTERWEIGHT REMOVAL DEVICE Lyle D. Grider, New Berlin, Wis., assignor to Bucyrus- Erie Company, South Milwaukee, Wis., a corporation of Delaware Filed May 20, 1966, Ser. No. 551,606 3 Claims. (Cl. 280-150) ABSTRACT OF THE DISCLOSURE A transit crane includes a working frame with a counterweight removably mounted at the lower rear edge thereof. A pair of levers are vertically pivotally mounted intermediate their ends at the rear of the frame, and have their upper ends releasably connected to the counterweight. A pair of double acting hydraulic cylinders are connected and operable between subframe units and the lower ends of the levers to pivot them between a generally vertical, mounted position in which the counterweight is raised and against the frame and a generally horizontal, dismounted position in which the counterweight is lowered and removed from the frame. The points of connection of the levers to the counterweight are above and slightly forward of the points of connection of the levers to the frame when the counterweight is mounted to have an over center effect, and the levers have extensions which extend forwardly when the counterweight is mounted and are releasably connected to the frame to lock the counterweight in place.

This invention relates to a counterweight removal device for truck mounted cranes and like machines; and it resides more particularly in an arrangement including a level vertically pivotally mounted on a working frame portion of the machine; a counterweight releasably connected to the lever and movable therewith between mounted and dismounted positions; and an actuator to effect reciprocal pivotal movement of the lever.

Many truck mounted cranes and similar machines are provided with heavy counterweights, and it is often desirable to have such counterweights readily removable. -In a large truck mounted crane, for example, the total weight per axle with the counterweight in place may well exceed legal limits for highway travel. When the machine is to be transported, therefore, it is desirable to be able to remove the counterweight and transport it separately.

Various devices for removing counterweights have been developed, and can be found in prior art patents. Prior arrangements have not, however, proven entirely satisfactory from the standpoint, for example, of cost, complexity, strength, safety and/or ease and efiiciency of operation.

It is the general object of this invention to provide an improved counterweight removal device that is relatively simple and inexpensive, that has great mechanical strength and that operates safely, easily and elficiently.

It is one specific object of the invention to provide an arrangement in which a pivotal lever is used to move a counterweight to both its mounted and dismounted positions.

It is another object of the invention to provide an arrangement utilizing a double-acting hydraulic cylinder as an actuator.

It is a further object of the invention to provide a counterweight removal device in which the counterweight is, when mounted, in an over-center position so that it is secure, which further includes a lock means to lock the counterweight in its mounted position.

It is another object of the invention to provide an arrangement in which the lock means and a connection Patented Mar. 26, 1968 between a counterweight and lever are easily and safely accessible.

It is a further object of the invention to provide an arrangement especially suited for a truck mounted crane in which the counterweight may be lowered to the bed of the carrier vehicle and disconnected and the working platform can then be rotated past the counterweight without interference so that the boom can be used to transfer the dismounted counterweight to another vehicle.

Other objects and advantages will appear from the description to follow. In the description, reference is made to the accompanying drawings, which form a part hereof, and in which there is shown, by way of illustration and not of limitation, a preferred embodiment of the invention.

In the drawings:

FIG. 1 is a somewhat schematic side view of a truck mounted crane incorporating a counterweight removal device according to this invention,

FIG. 2 is a fragmentary, enlarged top view, with parts broken away, further illustrating the device of FIG. 1,

FIG. 3 is a fragmentary view in cross section through the plane 3-3 shown in FIG. 2, and

FIGS. 4 and 5 are fragmentary views in perspective further illustrating the device of FIG. 1.

Referring again to FIG. 1, the truck mounted crane shown therein is more or less conventional in overall construction and includes a carrier vehicle designated generally by the reference numeral 1. Rotatably mounted on the bed 2 of the vehicle 1 is a working frame, designated generally as 3, which supports a hydraulically operated boom 4 as well as other usual elements. The frame 3, with the boom 4, is rotatable through a full circle in the usual manner. Since the construction and operation of such cranes is well understood by those skilled in the art, and since the invention is useful in other environments, the various elements thereof are not shown and will not described in detail.

A heavy counterweight 5 is, when in place, at the rear of the working frame 3, to the left as seen in FIG. 1. As can be seen in FIG. 3, both the counterweight 5 and the rear of the frame 3 are generally arcuate.

The frame 3 includes a pair of generally parallel subframe units 6, each of which includes an inclined top member 7 and a vertical end member 8 disposed at the rear edge of the frame 3. The members 8 are channel shaped and open inwardly toward the frame 3.

Extending outwardly or rearwardly from each member 8 are a pair of spaced, apertured ears 9. A pair of levers 10 are pivotally mounted intermediate their ends between respective sets of ears 9 by means of transverse pins 11, the levers 10 thus in effect being vertically pivotally mounted on the frame 3.

A pair of conventional double acting hydraulic cylinders 12 have their cylinder ends pinned to the underside of respective subframe top members 7 so that one end of each cylinder 12 is in effect pivotally connected to the frame 3. The extensible piston 13 of each cylinder 12 is provided with a clevis fitting 14 which receives the lower end, as seen in FIGS. 3 and 5, of the associated lever 10 and is pivotally connected thereto by means of a transverse pin 15. The web of each frame member 8 is provided with a lower opening 16 through which the associated piston 13 and clevis 14 may pass. The cylinders 12 serve as actuators for the levers 10 as will be described.

The other, upper end of each lever 10 is provided with a transverse opening 17, by means of which it is releasably pivotally connected to the counterweight as will be described. Each lever 10 is further provided with an inwardly or forwardly extending extension 18 which, as seen in FIG. 5, extends through an upper opening 19 in the web of the associated frame member 8. The flanges of the member 8 and the inner end of the extension 18 are provided with openings which are in alignment when the lever 10 is in the position of FIG. and which removably receive transverse lock pins 20. A well 21 is provided in the frame 3 between the subframe units 6, and an operator standing therein can easily insert and remove both lock pins 20.

The counterweight 5 is provided with two cavities 22, one of which is seen clearly in FIG. 4, which open through its top and which face respective levers At the upper center portion of each cavity 22 is a large boss 23 provided with a vertical, downwardly opening slot 24 and aligned transverse openings 25.

As seen in FIGS. 2 and 3, the slots 24 receive the upper ends of respective levers 10, and removable transverse connecting pins 26 are passed through the openings 17 and 25 to affect a releasable pivotal connection between the counterweight 5 and levers 10. The cavities 22 afford access to the pins 26 and allow them to be inserted and removed from above by the operator.

The counterweight 5 is provided with lower bearing surfaces 27 below each cavity 22 which are adapted to bear against the frame 1. The upper portions of the bosses 23 are shaped to define inclined upper bearing surfaces 28. The surfaces 28 are adapted to bear against the heads of bolts 29' at the ends of the frame members 7, the bolts 29 being threadedly adjustable inwardly and outwardly to vary the orientation in which the counterweight 5 bears against the frame 3 when in place.

In FIGS. 1-3, the counterweight 5, as seen in full lines, is in a mounted, working position wherein it is raised and close to the frame 3. The levers 10 are vertical and the pins 20 are in place. The pistons .13 are extended. In this position, the bearing surfaces 27 are against the frame 3 and the bearing surfaces 28 are against the bolts 29. The weight of the counterweight is carried primarily by the pins and 26 and to a lesser extent by the pins and the bolts 29. As can be seen in FIG. 3, the counterweight 5 is, when mounted, in an over-center position, with the pins 26 slightly to the right, as seen in FIG. 3, of the pins 11. This reduces any tendency for the counterweight 5 to move to the left, away from the frame 3, during working. The pins 20 serve to lock the levers 10 in place with respect to the frame 3 and thus to lock the counterweight 5 in mounted position.

When the counterweight 5 is to be dismounted, the frame 3 is first rotated to bring the counterweight 5 directly over the bed 2, as seen in FIG. 1. The pins 20 are then removed by the operator, the well 21 providing a suitable place for the operator to stand. The cylinders 12 are then actuated to retract the pistons 13, thus pivoting the levers 10 in counterclockwise fashion as seen in FIG. 3. The counterweight 5 is thereby moved to its dismounted position, seen in broken lines in FIGS. 1-3, wherein it is lowered and removed from the frame 3 and rests on the bed 2.

The operator then removes the pins 26 to disconnect the counterweight 5 from the levers 10 and frame 3. In the embodiment shown, the cavities 22 open through the top of the counterweight 5 so that the pins 26 can be reached from above. The cavities 22 also afford access from the side, however, so that it is not absolutely necessary to have the cavities 22 open upwardly and the top of the counterweight 5 can be made solid to provide extra mechanical strength if desired.

The levers 10 are then pivoted, by means of the cylinders 12, back to the vertical positions corresponding to the mounted position of the counterweight 5 where they are clear of the counterweight 5. The frame 3 can then be rotated past the counterweight 5 without interference 4. p to bring the boom 4 in place so that it can be used to lift the counterweight 5 and transfer it to another vehicle or the ground. The slots 24 extend upwardly far enough to accommodate the lever extensions 18 during dismounting and to allow the levers 10 to be moved back to vertical positions after disconnection.

To effect remounting, the counterweight 5 is first moved to its dismounted position on the bed 2 in appropriate fashion and the frame 3 is moved to the position of FIG. 1. The levers 10 are pivoted to place their upper ends within the slots 24, and the pins 26 are inserted. The pistons 13 are then extended to pivot the levers 10 in clockwise fashion, causing the counterweight 5 to be moved upwardly and inwardly back to its mounted position. The pins 20 are finally reinserted.

The hydraulic circuit for the cylinders 12 is not shown or described herein since such circuitry is well understood by those skilled in the art. It is important to note, however, that the lock pins 20 make circuitry problems considerably simpler by eliminating the need to rely on check valves to hold the counterweight 5 in place. That is, without the pins 20, any retraction of the pistons 13 as the result of bleeding could cause the counterweight 5 to lower. Although there should still be appropriate check valves, the pins 20 insure that the counterweight 5 will remain locked in place regardless of any hydraulic failure.

Although a preferred embodiment of the invention has been shown herein, it will be apparent that modifications in structure and use may be made without departing from the spirit of the invention. The invention is not, there fore, intended to be limited by the disclosure herein, or in any other way, except insofar as limitations appear specifically in the following claims.

I claim:

1. In a truck mounted crane or the like having a working frame and a counterweight removably mounted at the rear of the frame, the combination therewith of: a lever vertically pivotally mounted intermediate its ends on the frame near the rear thereof; a releasable pivotal connection between the upper end of the lever and the counterweight; and a hydraulic cylinder connected and operable between the frame and the lower end of the lever to affect pivotal movement thereof, the lever being pivotal between a mounted position wherein it is generally vertical and the counterweight is raised and close to the frame, the point of connection of the counterweight to the lever then being generally above the point of mounting of the lever on the frame, and a dismounted position in which the lever is generally horizontal and the counterweight is lowered and removed from the frame.

2. The combination of claim 1 wherein the point of connection of the counterweight to the lever is at least slightly forward of the point of connection of the lever to the frame when the lever is in its mounted position.

3. The combination of claim 2 wherein the upper end of the lever is provided with an extension which extends forwardly when the lever is in its mounted position; and wherein there are means to releasably connect the extension to the frame to lock the lever in its mounted position.

References Cited UNITED STATES PATENTS 3,278,045 10/1966 Potter et al. 212-49 BENJAMIN HERSH, Primary Examiner.

LEO FRIAGLIA, Examiner.

J. S EGEL, Assistant Examiner,

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3,375,021 March 26 1968 Lyle D. Grider It is certified that error appears in the above identified patent and that said Letters Patent are hereby corrected as shown below:

Co'lunm I, line 11,, "tra crane" should read truck mounted grane l ne 52 "standpoint" should read standpoints oolumn 2 line 38, after "not" insert be Signed and sealed this 29th day of July 1969.

(SEAL) Attest:

WILLIAM E. SCHUYLER, JR.

Edward M. Fletcher, Jr.

Commissioner of Patents Attesting Officer 

